London's Southwark Crown Court was told the fact they had never met did not prevent the trio "drooling" over the possibility of turning

sick fantasies into chilling reality.

They even referred to doing a "Holly and Jess" - a harrowing reference to the Soham 10-year-olds brutally murdered by Ian Huntley in 2002.

Police first heard of their twisted plan when "rape obsessed" David Beaven, got cold feet, walked into Bournemouth Police Station and told them what had been going on.

Beaven, 42, a greeting card salesman, of Shackleton Square, Bransgore, Hampshire, claimed he was just a "vigilante" gathering evidence against paedophiles but he was convicted of two counts of conspiracy to rape.

Film make-up artist Alan Hedgcock, 41, from River Way, Twickenham, south west London was convicted of conspiracy to rape at an earlier hearing.

Unemployed Robert Mayers, 42, who lived in Brighton Street, Warrington, Cheshire, also denied any wrongdoing but was similarly convicted.

Beaven was given an indeterminate prison sentence with an 11 year tariff.

Hedgcock unsuccessfully argued he was simply the victim of an overactive imagination.

He, too, was given a similar sentence but with an eight year tariff after being found guilty of one of the charges.

Mayers was also given an eight year tariff.

In addition, all three variously admitted 50 sample counts of distributing, making and possessing thousands of indecent images of children.

Passing sentence Judge Geoffrey Rivlin QC, said because the men posed a "serious risk of physical and psychological harm to children", they would also be required to register as sex offenders for life.

They would also have to undergo a sex offenders treatment programme in prison and be subject to a sex offenders prevention order closely controlling their contact with young children, accessing the internet and possessing photographic equipment.

He said the chatroom logs of their discussions about their plans for the girls were of the "most lurid and disgusting kind".

"You were drooling over the prospect to take these children into the woods and rape them.

"These logs were further spiced, if that is the right word, by the swapping of pornographic images of young children.

"All three of you were found to be in possession of very many photographs of children, some of them...very shocking."

Dealing first with Beavan - who was said to have a "pattern" of turning himself in to the authorities - had tried to put him forward as "something of a vigilante".

"But you were very deeply committed to the sexual exploitation of young children.

"I must consider that real children were involved here, some of whom were so very young it is extremely difficult to comprehend your sexual interest in them. I've even seen photographs of infants."

The judge said apart from the fact he had been convicted of two rape conspiracies, his case was particularly serious because of his "widespread distribution" of some of the images.

It was clear he suffered from a personality disorder with "episodes of bizarre and disturbing behaviour", and probably the only reason he went to the police was because he feared he was about to be arrested anyway.

"I am satisfied you pose, at the very least, a risk of causing serious harm both physically and psychologically to both women and children," the judge added.

The judge told Hedgcock he had a "blatant disregard for the safety of children".

Character testimonials in his favour described him as humorous, generous, considerate...and "a thoroughly nice bloke".

"But they knew nothing at all about this dark side to your character."

The judge added: "Your counsel express some incredulity that you had been charged with the rape and conspiracy offence.

"But when a man promotes the rape of a particular child in a particular place which he obviously thought about and descends to detail he should not be altogether surprised if he is taken at his word."

Mayers was told that like the others he, too, posed a "serious risk" to children despite his previous good character.

Outside court Detective Constable Dave Adams, of the Met's Child Abuse Investigation Command, said: "These three men took a step beyond fantasy and have actually identified the children they would target, the location where they would approach them and what exactly they planned to do to them. It is appalling to consider the potential repercussions if that hadn't come to police notice.

"This is a really significant investigation because, for the first time, internet chat logs have been used to prove a charge of conspiracy to rape a child. This case should act as a really stark warning that the internet is not a hiding place to plan and participate in criminal acts."

A Dorset Police spokesman said: "We are pleased to have been involved at the very beginning of this investigation. Our specialist sex offenders unit and high-tech crime unit officers quickly realised that there were very serious offences in the Metropolitan Police area.

"We liaised with them at a very early stage - and the painstaking and thorough Metropolitan Police investigation has seen today's successful conclusion."

During the men's trial, the court heard that after stumbling across each other in an incest chatroom, "child porn addict" Hedgcock told Beavan how he wanted to abuse two sisters aged 13 and 14.

His plan was to pounce as they walked through woods to school. Beavan immediately made it clear he was interested, but emphasised he did not like time wasters.

"I hope you are not a fantasist," he said. "I have no limits," added the man, who also confessed to police contemplating killing his wife and going through "throttling motions" with a prostitute.

Jurors heard he was so keen he later used the internet to recruit Mayers.

But Beavan eventually lost his nerve when he thought the authorities might be closing in and betrayed the others.

After his arrest, police found more then 5,000 child porn images on his computer, 1,249 of which were downloaded in a single session.

Beavan did not give evidence but instead insisted through his counsel that his internet forays were purely for "research" purposes.

He claimed that after meeting Hedgcock, and the make-up artist mentioning doing a "Holly and Jess", he decided to go along with the conversation, and in a statement to police he maintained he was interested only in adult chatrooms and that his discussions about raping the underage girls were "pure fantasy".